1 Topic by pastprimitive

  • pastprimitive
  • Member
  • Offline
  • Registered: 2013-02-23
  • Posts: 206

Topic: Clipping oozing filament before print starts...

So I was wondering if anyone had a good solution for this annoyance.  Whenever I preheat my SD3 before a print I always have to make sure to clip the small amount of oozing filament that comes out of the extruder. If I don't it often will come loose in unpredictable places and get caught up in my print. I was wondering besides using more skirt passes has anyone come up with a nice automatic solution that doesn't require babysitting before print start?

One thought I had was to amend my start gcode so that instead of the extruder moving over the print bed, waiting for the extruder to reach target temp, then drop and begin print; if I simply had it wait in the dump area at Z "0" and then have it move over to the start position so the edge of the aluminum bed would serve as a knife edge to scrap the excess oozing filament off. Any thoughts? Bad idea...

2 Reply by cmetzel

  • cmetzel
  • Member
  • Offline
  • From: Solidoodle2 #0091
  • Registered: 2012-08-22
  • Posts: 1,429

Re: Clipping oozing filament before print starts...

I can't remember who, maybe lawsy had start gcode that did just what you're describing.

3 Reply by pastprimitive

  • pastprimitive
  • Member
  • Offline
  • Registered: 2013-02-23
  • Posts: 206

Re: Clipping oozing filament before print starts...

Ahah! I'll have to amend mine and give it a whirl!

4 Reply by blarz

  • blarz
  • Member
  • Offline
  • From: Hazleton, PA
  • Registered: 2013-06-26
  • Posts: 72

Re: Clipping oozing filament before print starts...

Did you find it? Can you re-post or direct others to it?

SD3/SD4 Mods completed: glass bed, changed zrod to 5mm, slop nut, aluminum arm-originally wood, plexi-glass case, Z Wobble Preventer,  Lawsy Carriages, X\Y motor fans, control board fans, extruder cartridge heater, MK5, Esd Lite
Mods working on:Direct Y Drive
Remember.......All you touch and all you see is all your life will ever be....Pink Floyd...Dark Side of the Moon.

5 Reply by pastprimitive

  • pastprimitive
  • Member
  • Offline
  • Registered: 2013-02-23
  • Posts: 206

Re: Clipping oozing filament before print starts...

I was planning on just writing it myself. It should be a really simple gcode change.  As soon as I do it i'll post the code.

6 Reply by MolecularConcept

  • MolecularConcept
  • Member
  • Offline
  • From: Pennsylvania
  • Registered: 2013-06-03
  • Posts: 392

Re: Clipping oozing filament before print starts...

when i changed my start gcode my anchor never stay put it always got drug around the bed and other times it didnt work at all

7 Reply by pastprimitive

  • pastprimitive
  • Member
  • Offline
  • Registered: 2013-02-23
  • Posts: 206

Re: Clipping oozing filament before print starts...

Here is the amended gCode to solve my filament oozing issue. 

Not really much different then the standard gCode start code.  The only difference is the extruder head waits after autohome in the dump area to the right while it heats up. once done it moves over to the standard start position. Something like X195 Y195 Z0, lowers the bed 5mm, then raises it back to whatever your first layer height is set in your Sli3er profile. I almost left out the lower bed 5mm code thinking it was pointless. But then I realized this was most likely to take care fo any backlash issues on the Z-axis after auto homing.  So I left it in. Just made sure it happened right after the filament got clipped by (in my case) the edge of my glass sheet on my AL bed. 

G21; set mm units
G28 ;home all axis
G90; set absolute coordinates
G92 E0; reset extruder distance
M104 S200; set extruder temp and start heating
M109 S200; wait for extruder temp to be reached
G1 X195 Y195 F3000 ; move to back right corner
G1 Z5 F300 ;move platform down 5mm
G1 Z[first_layer_height] F200 ;move platform close to nozzle
;G1 E7; extrude anchor
G1 F3000; center print head
G92 E0; reset extrusion distance

Anyhow, hopes this helps. Works brilliantly for me.